Casktoberfest

Casktoberfest was a private homebrew festival featuring both gravity service and beer engines. At its peak, there were two pins and six engines plus a variety of bottles. To simplify future events the host has decided to eliminate the engines in favor of a more permanent draft setup. As he put it, easier to clean and setup, which it most definitely is.

This festival had the advantage of being installed in a private garage workshop in October, which meant that it naturally maintained cellar temperature at this time of year. The pins and kegs were brought in early in the week leading up to the event and had plenty of time to settle in position. The pins in their cradles were allowed to sit a day or so before venting. The kegs were also vented although this was simply opening the pressure relief valve and allowing the head pressure out. Typically the kegs had to be vented several times in the days leading up to the event as they do not breathe as the pins could.

When serving from a beer engine, any keg can do the job of holding the conditioned beer. Cornelius kegs are the easiest because they can be completely opened up for cleaning out the yeast slurry but any keg would work. The timing of this festival allows for the kegs to also serve as the conditioning vessels just as a pin or firkin could. The same calculations apply for the desired dissolved volumes of CO2.

After the first year we used beer engines, we discovered that it was advantageous to cover the beer with CO2 instead of allowing atmosphere in. We simply didn’t drink all of the beer and there was significant waste. The kegs worked great for this purpose as they are designed to accept CO2. The only ‘trick’ was to set the regulator on the CO2 supply to zero. While some may inevitably bleed past, spread over all of the kegs (each of which already had CO2 in solution) the actual addition was sure to be negligible. [ SIDE BOX] Pure CO2 is preferred over a beer mix or pure N2 (or argon) because partial pressure of the non-CO2 gas would inevitably result in the beer giving up more condition than desired due to diffusion pressures. Over the time scale of this event this would be negligible but we were looking to preserve the extra beer for home consumption. There was no reason to mix gasses. In an actual cellar setting, cask ale does slowly lose its condition for just this reason. Atmospheric mix is __% N2, __% O2 and __% CO2 with a host of trace gasses. Temperature and vessel configuration (constriction point at tut reduces constant mixing with unequalibrized air) do help preserve condition but flat beer is inevitable.[/SIDE BOX] For our purposes, we used a single CO2 tank and a manifold to connect all of the gas-sides together.

Connecting the beer engines to the kegs was trivial. The beer engines that we were using had a ½” barb input. We used ¼” MFL ball-lock connectors with ½” FFL swivel barbs. Reinforced tubing is necessary so that the vacuum created does not collapse the tube. We didn’t need to insulate because of the configuration (kegs and tubing were under cover, venue maintained proper temperature) but doing so is easy with pipe insulation and duct tape.

Before pulling beer through the line, be sure to pull (warm) cleanser through, (warm) rinse, then cold sanitize. I prefer an iodine-based sanitizer mixed to no-rinse strength (3 mL / G). I like to pull the cleanser through until it is clear, then cycle it back into the source bucket for 8-12 pulls and let it sit in the line for 10-15 minutes. Agitating the cleanser inside the engine is its own reward. You’ll have to hang the open end over the handle as it will just siphon out if left low. After sitting, pull though to empty, then pull rinse water. 8-12 pulls is fine. Do not recycle. Pull through, then cycle the sanitizer for 5-6 pulls. Leave packed until you’re ready to connect up the lines. Pull through before connecting so that you can’t possibly mix beer and sanitizer! Once connected, pull through until you get a solid stream, then take another pint (2-3 pulls). There is plenty of beer and it is not worth the hassle of worrying about early yeast sediment. Just pull it through and dump it.

Attendees got a kick out of pulling their own pints. It’s really fun! There is only one real thing to troubleshoot with engines: excessive foam in the glass. Here’s a list of common causes and possible solutions:

• The line is not air-tight and is pulling air in somewhere. Check connection at kegs and at bottom of engine. Usually it’s the one on the bottom of the engine.
• The beer is over-conditioned. It is degassing in the cylinder. Disconnect the gas supply and make sure that the keg is sealed. As people pull additional pints, the head pressure in the keg is reduced (increasing volume for set gas concentration). This pulls additional CO2 out of solution to help equalize it. Eventually the keg will become locked and the handle really hard to pull. Reconnect the gas supply and try the beer. Be careful that you don’t remove too much condition!
• Internal seal leakage. Not much you can do unless you have a seal replacement kit and know how to use it. This one just has to be dealt with for the duration of the event.

At the conclusion of the event, the very least that has to be done is to disconnect the gas and liquid sides of all of the kegs. To prepare the beer engines for storage, you’ll need to pull through cleanser & sanitizer as before (sanitization before storage prevents mold growth due to moisture). Tilt and shake the engine every which way to remove as much sanitizer from the piston as possible.